Magnetic removal ofstickiesfrom waste papers

摘要

An improved process is disclosed for removing "stickies" from waste paper which contains hot-melt and pressure-sensitive adhesives and lattices to produce high quality (high brightness, little to no dirt content) pulp with little or no fiber loss. The process involves attachment of sticky particles in the waste paper pulp to a magnetic carrier material with the help of an agglomeration agent followed by removal of the attached sticky particles by magnetic separation. The magnetic treatment preferably is conducted at ambient or greater temperature, at neutral to alkaline pH and at a low pulp consistency. Agglomeration and magnetite addition, followed by exposure of the repulped waste paper to a magnetic field provides near complete sticky removal over exposure to the magnetic field without such pre-treatment.